The theme of the Gulf South Sexually Transmitted Infections/Topical Microbicide Cooperative Research Center (STI TM CRC) is "Women at high risk for STI's: Focusing research where it is needed the most." There will be four projects and four cores within this CRC. The four projects will focus on the following: 1. Cervical T cell responses to chlamydial infection, 2. The role of Mycoplasma genitalium in infertility in women. 3. The biology of toll-like receptors (TLRs) in genital tract tissues and the potential of TLR agonists as new topical microbicide candidates for use in preventing STI's in high risk women. 4. The role of treatment failure and re-infection in recurrent Trichomonas vaginalis infections following metronidazole treatment. This CRC will have administrative, laboratory, clinical, and biostatistics cores. In addition there are two special aspects of this application. One is a mid-career mentoring program designed to provide senior level guidance to mid-career investigators endeavoring to reach the top of their chosen scientific fields. The other is an important effort to develop modern molecular methods for the study of the vaginal ecosystem that will be included within the Laboratory Core. Our Gulf South STI TM CRC application proposes to create a new CRC in the heart of an area whose population suffers disproportionately from the long term sequelae of STIs. Funding this center will have significant social and public health impact on STIs in this high risk region for many years into the future.